Recently, researches of robots that can do a lot of things for convenience of people are being actively carried out. These robots often go through complicated paths to reach desired positions.
In order to solve such a problem, an omnidirectional driving mechanism has been developed. The omnidirectional driving mechanism refers to improving motion ability of a robot or the like to enable movement in three degrees of freedom (forward/backward movement, leftward/rightward movement, and rotation) on a 2-dimensional (2D) plane (flat surface) such that the robot can travel in an arbitrary posture along an arbitrary direction.
There are various omnidirectional driving mechanisms. Among others, an off-centered wheel mechanism is a typical mechanism using the related art wheel. In order to perform an omnidirectional movement, a steering shaft is installed on each wheel at a predetermined distance from a center of the wheel, so as to steer the wheel to move in an omnidirectional manner.
Examples of wheels specially designed to omnidirectionally move includes an omnidirectional wheel, a universal wheel, a Mecanum wheel, a double wheel, an alternate wheel, a half wheel, an orthogonal wheel, a ball wheel, and the like.
Among others, the omnidirectional wheel is not easily moved at a place where a small step is formed. In addition, there are many contact points with the ground, thereby generating a lot of vibration while the wheel is driven.
In the omnidirectional wheel type, an impact or vibration is generated when a rotating direction of an outer wheel is reversed to the front and rear of a barrel wheel, and an impact due to the reversed rotating direction also increases in the vicinity of the barrel wheel as a width of the barrel wheel is small.